1. Priority Claim
This application claims the benefit of priority from European Patent Application EP 11 156 653.5 filed on Mar. 2, 2011.
2. Technical Field
The present invention relates to a method for determining a number of floors of a building and to a module system determining the number of floors.
3. Related Art
Navigation systems provide driving recommendations for a driver of a vehicle. These navigation systems may provide driving recommendations by simply indicating an arrow indicating the driving direction. Furthermore, map data showing a network of roads may be displayed in a bird's eye perspective to the driver. The recommended route may then be highlighted on the road network shown on the display together with driving recommendations.
In recent years the displayed navigation information became more and more user-friendly and it is known to display a three-dimensional perspective of the scene on a display as seen by the driver. In this context the buildings neighboring the roads are displayed in addition to the roads.
There exist databases including image data of the road network including the vehicle surrounding. In these image data buildings or other monuments as seen from the road are shown. The amount of data needed to provide images of the surrounding in a larger geographical area is quite large, as normally a picture of a building showing the façade of the building includes approximately 2 Megapixel. These detailed image data may not be used in connection with a navigation system incorporated into a vehicle which contain map data of a whole country or a whole continent. At the same time a three-dimensional representation of a vehicle surrounding is needed in which the user of the map data to which the three-dimensional representation is shown may at least recognize the displayed buildings shown in vehicle surrounding when the displayed buildings are compared to the reality when looking out of the window. This is possible when the number of floors of a displayed building corresponds to the number of floors of the building in reality.
Therefore, there exists a need exists to provide a possibility to efficiently and reliably determine the number of floors of a building shown on image data.